The present invention relates generally to equipment for servicing vehicle brakes. More particularly, the present invention relates to an on-car brake lathe having an improved support trolley.
It is well-known that the brake rotors of a disc brake must be periodically resurfaced in order to maintain optimum braking capacity. Traditionally, brake rotors have been resurfaced using a bench-mounted lathe. This process requires removing the rotor from the vehicle, machining the surface of the rotor on the bench-mounted lathe, and reinstalling the rotor. As one skilled in the art will appreciate, such a process requires substantial time and labor.
Unlike a bench lathe, an on-car brake lathe does not require removal of the brake rotor from the vehicle. Instead, the lathe device is attached to the vehicle hub so as to machine the rotor in place. An example of an on-car lathe is described in U.S. patent application Ser. No. 09/611,535, assigned to the assignee of the present application, and incorporated here by reference.
A typical on-car lathe weighs 60-100 pounds and includes a motor and drive shaft for turning the rotor, as well as cutting tools for machining the rotor surface. In addition, the on-car lathe includes a mechanism for attaching the lathe to the hub and aligning the lathe with the hub. That is, the drive shaft of the lathe motor should rotate about the same axis as the hub so the cutting tools will machine the rotor surface perpendicular to the hub""s axis of rotation.
In practice, the on-car brake lathe must be mounted on the hub of a vehicle that is elevated on a hydraulic lift in a garage. Therefore, to be functional, the operator must be able to maneuver the lathe around the garage between various obstacles, such as other vehicles. In addition, the operator must raise or lower the lathe and change the orientation of the lathe to facilitate convenient and accurate alignment with the hub.
Current lathe support systems for on-car brake lathes generally employ a three spoke base with wheels for movement. Either a counterbalance or mechanical support structure is provided to adjust the height to facilitate attachment of the lathe to the vehicle.
A counterbalance support system uses a spring or gas shock located in a vertical telescoping structure to counterbalance the weight of the lathe at a single height. Although a counterbalance system is adequate for a single height, considerable operator effort is required to position the lathe at a height other than the equilibrium.
A mechanical support system uses a screw, ratchet, or hydraulic piston to raise or lower the lathe. Although this type of support system allows the operator to adjust the static height of the lathe, the adjustment is cumbersome, slow, and rigid.
The present invention recognizes and addresses the needs discussed above and others of prior art constructions and methods. Accordingly, it is an object of the present invention to provide an improved support trolley for an on-car brake lathe.
It is an additional object of the present invention to provide a support trolley that allows the operator to smoothly raise or lower an on-car brake lathe.
It is also an object of the present invention to provide a support trolley in which the nominal support height can be easily adjusted by an operator.
Some of these objects are achieved by an apparatus comprising an on-car brake lathe device and a trolley supporting the on-car brake lathe device. The trolley has a cylinder assembly including a cylinder housing, a piston located within the cylinder housing and a piston rod attached to the piston. The on-car brake lathe device is connected to the trolley such that relative reciprocative movement between the piston and the cylinder housing causes raising and lowering of the on-car brake lathe device. The piston defines an equalizing port for gas communication between an upper chamber and a lower chamber of the cylinder housing.
In some exemplary embodiments, the cylinder includes valve means for introducing and releasing air from the cylinder housing. For example, the valve means may comprise a SCHRADER(copyright) style valve.
Often, the trolley may further include a base structure and a mounting structure to which the on-car brake lathe is connected. The cylinder assembly is located between the base structure and the mounting structure. In many cases, the cylinder will be inverted such that a distal end of the piston rod is attached to the base structure. The cylinder housing, in turn, is attached to the mounting structure in such embodiments.
In some cases, the mounting structure may comprise an offset member adapted so that the on-car brake lathe will be located directly above the cylinder assembly. In addition, it will often be desirable to configure the apparatus such that the on-car brake lathe device will be pivotally connected to the trolley. A locking mechanism may be provided to lock the on-car brake lathe device in a selected pivoted position.
Other objects of the present invention are achieved by a trolley for supporting and positioning a piece of equipment. The trolley comprises a base structure and a mounting structure to which the piece of equipment is connected. A cylinder assembly is connected between the base structure and the mounting structure. The cylinder assembly includes a cylinder housing, a piston located within the cylinder housing and a piston rod attached to the piston. The piston separates first and second gas chambers in the cylinder housing. In addition, the piston defines an equalizing port to permit gas communication between the first and second chambers.
Other objects, features and aspects of the present invention are provided by various combinations and subcombinations of the disclosed elements, as well as methods for practicing the same, which are discussed in greater detail below.